1. Field of the Invention
The present invention relates to a semiconductor device cooling apparatus used to cool a semiconductor device with a liquid.
2. Description of the Related Art
Heretofore, various types of structural parts for cooling semiconductor devices are proposed, and, in particular, various groove type and tube type coolant flow path structures are conventionally used often to a semiconductor device cooling apparatus called a cooling plate that is used to cool a semiconductor device by a fluid.
FIGS. 1(A) and 1(B) are views showing a schematic structure of a cooling plate having groove type flow paths, wherein FIG. 1(A) is a sectional plan view of the cooling plate taken along the arrow-carrying line X—X of the cooling plate shown in FIG. 1(B), and FIG. 1(B) is a side view of the cooling plate.
The cooling plate 20 includes a heat transmission plate 21, a semiconductor device 10 is joined to an outer surface 21a of the heat transmission plate 21 through a joint member 11, and the flow paths described below are formed along an inner surface 21b of the heat transmission plate 21. That is, a coolant (here, water is used as an example of the coolant) is supplied from a coolant supply port 22, and water as the coolant flows on the inner surface 21b of the heat transmission plate 21 through groove type flow paths 24a formed between standing fins 23a, further flows on the inner surface 21b of the heat transmission plate 21 passing through groove type flow paths 24b formed between standing fins 23b, and is discharged from a coolant discharge port 25.
The cooling plate 20 having the groove type flow paths 24a and 24b is disadvantageous in that the structure of it is complex and a manufacturing cost is expensive, although a high cooling performance can be easily obtained when the semiconductor device 10 is cooled thereby.
FIGS. 2(A) and 2(B) are schematic configurational views of a cooling plate having a tube type flow path, wherein FIG. 2(A) is a plan view of the cooling plate, and FIG. 2(B) is a side view of the cooling plate.
The cooling plate 30 shown in FIGS. 2(A) and 2(B) has a somewhat thick heat transmission plate 31, and a semiconductor device 10 is joined to an outer surface 31a of the heat transmission plate 31 through a joint member 11.
Further, a tube type flow path 32 is formed in the heat transmission plate 31. A coolant (for example, water) supplied from a coolant supply port 33 passes through the tube type flow path 32, receives heat transmitted thereto through the heat transmission plate 31 while it passes through the flow path 32, and is discharged from a coolant discharge port 34.
While the cooling plate having the tube type flow path as shown in FIGS. 2(A) and 2(B) can be made at a relatively low cost, the cooling plate is disadvantageous in that it has a low cooling capability and it is difficult to reduce its size.
Further, although illustration is omitted, Japanese Patent Application Laid-Open Publication (JP-A) No. 10-246531 discloses a cooling structure arranged such that a semiconductor device 10 is joined to an outer surface 21a of a heat transmission plate 21 as shown in, for example, FIG. 1, and laminar flow paths are formed along an inner surface of the heat transmission plate 21 so that a coolant flows in one direction, for example, from right to left in the figure in parallel with the inner surface of the heat transmission plate 21.
In the flow path structure of JP-A 10-246531, since the laminar flow paths are formed along the inner surface of the heat transmission plate, a heat absorption performance higher than that of the flow path structure shown in FIGS. 2(A) and 2(B) can be obtained. However, since the coolant flows in the one direction, for example, from right to left, it has a temperature gradient between the right side and the left side thereof, from which a problem arises in that the coolant has a different heat absorption capability on the right side and the left side of a semiconductor device and it is difficult to uniformly cool the semiconductor device by the flow path structure.